Not graded
Muttafaq ‘alayh (Bukhari and Muslim) Riyad as-Salihin 1592
The Messenger of Allah (ﷺ) said, "It is not lawful for a Muslim to desert (stop talking to) his brother beyond three nights, the one turning one way and the other turning to the other way when they meet, the better of the two is one who is the first to greet the other." [Al-Bukhari and Muslim].
"لا يحل لمسلم أن يهجر أخاه فوق ثلاث ليال: يلتقيان، فيعرض هذا ويعرض هذا، وخيرهما الذي يبدأ بالسلام"